West London Mental Health Trust unveiled its latest framework contractors on a £24m spending programme that covers Broadmoor and other health facilities in London.
The trio and Kier Regional also picked up places for a £12m programme of building and M&E work at other sites.
The frameworks come as the Trust begins to gear up for a £250m expansion of the high-security psychiatric hospital in Berkshire.
Its plan is to build a new hospital containing 234 beds alongside the existing 1863 Victorian listed buildings.
A spokesman for Broadmoor Hospital Trust said the plan is to start construction of the new hospital in 2013, but there are still land use and funding issues to be sorted out.